05000289/FIN-2015002-01
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Finding | |
|---|---|
| Title | Failure to Maintain Turbine Bypass Valve Simulator Modeling |
| Description | A self-revealing NCV of 10 CFR Part 55.46(c), Plant-Referenced Simulators, was identified for Exelons failure to ensure that the plant-referenced simulator demonstrated expected plant response to normal, transient, and accident conditions to which the simulator has been designed to respond. Specifically, Exelon failed to ensure simulator modeling of once through steam generator (OTSG) turbine bypass valve (TBV) operation was consistent with the actual plant which introduced negative operator training and challenged orderly unit shutdown on May 7, 2015. The licensee documented their corrective actions for this issue in TMI issue reports (IR) 02496279 and 2497542, which included software changes to the simulator to reflect actual system design, crew remediation, and procedure changes. The performance deficiency is more than minor because it is associated with the human performance attribute of the Initiating Events cornerstone and affected the cornerstone objective of limiting the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the simulator difference introduced negative operator training and, as a result, challenged orderly shutdown of the unit on May 7, 2015. The inspectors evaluated the finding in accordance with NRC Manual Chapter 0609, Significance Determination Process, and the corresponding Appendix I, Licensed Operator Requalification Significance Determination Process. The finding was determined to have very low safety significance (Green) because the impact on operator performance was not during a reportable event. This finding has no cross-cutting aspect assigned because the cause was not representative of current licensee performance. Specifically, the difference in TBV modeling existed since initial simulator certification on June 28, 1990. |
| Site: | Three Mile Island  |
|---|---|
| Report | IR 05000289/2015002 Section 1R20 |
| Date counted | Jun 30, 2015 (2015Q2) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | D Werkheiser J Heinly J Rady R Rolph S Kennedy |
| Violation of: | 10 CFR 55.46 |
| INPO aspect | |
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Finding - Three Mile Island - IR 05000289/2015002 | |||||||||||||||||||||||||||
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Finding List (Three Mile Island) @ 2015Q2
Self-Identified List (Three Mile Island)
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